Improvement in return tubular boilers



more rapidly generated with a less UNITED STATES PATENT OFFICE.

ROBERT EHMAN, OF VALLEJO, CALIFORNIA.

IMPROVEMENT IN `RETURN 'TuBuLAR BoiLERs.

' Specification forming part of Letters Patent N o. 185,434, datedDecember 19, 1876; application tiled A August 24, 1876.

To all whom it may concern:

Be it known that I, ROBERT EHMAN, of

' Vallejo, in the county of Solano and State of California, haveinvented certain new and useful Improvements in Return Tubular Boilersfor Steam-Engines; and I do hereby declare that the followingdescription and accompanying drawings are sufficient to enable anyperson skilled in the art or science to which my invention most nearlyappertains to construct and use the same without further invention orexperiment.

My invention relates, mainly, to that class of steam-boilers employed inlield or portable engines; and it consists, principally, of means forregulating and increasing the draft, and directing and conducting theheat to the return-fines, whereby combustion of the fuel is much morerapid and the product of combustion more fully utilized.

My invention also relates to the construction and arrangement of thewater-tubes and water spaces and jackets, whereby steam is quantity offue] than in the ordinary boiler now employed; and, also, to meansforventilating the outer shell and rear head or end of the boiler, allof which will hereinafter more fully appear. i

Referring to the drawings, and to the letters of reference markedthereon, Figure l is a longitudinal vertical section, with rear-end doorthrown back. Fig. 2 is a horizontal view in section, with outer shelland a portion of iire box or chamber; Fig. 3, front-end view, with outerdoor removed, and showing the deecting-collar in position; Fig. 4,rear-end View, with door closed.

A represents the outer shell of the boiler, and B the inner shell, whichsurrounds the fire-chamber grate-bars c c and tubes b b and short tubesb b. G G are the water-spaces, which connect with the tubes b b.Water-space, connecting with the main water-space of the boiler, andextending downward across the upper arch or crown of the heating or firechamber, so that the flame and heat, as it ascends, will come in contactwith this projecting water-heater before passing onward to the rear endof the boiler.

The water-tubes b b connect at one end Dis a with this water-space,their opposite ends extending into the main water-space A. These tubesare only about one-half the length of the tubes b b, and are alsolocated along the upper arc of the fire or furnace box, while the longtubes are located at both sides of the furnace-box, and extend from endto end of it, and enter the water-jackets U O, constructed at both endsof the boiler.

Thus it will be seen that the lire and heat have full play upon the longand short watertubes, the water-jackets C C, shell B, and water-space D,whereby the heat from the furnace is utilized in the best mannerpossible.

The rear end of the boiler is provided with a cold-air chamber, F, whichis perforated at h the top with holes f, which serve mainly as aventilator of that portion or end ofthe boiler which prevents the liningof the back connec tions from becoming heated and burning out. Beneaththis air-chamber is a hot-air space, E'.

A hinged door is attached to the rear end of the boiler, which isprovided with a delecting-plate, Gr, which is constructed independentot' the door-plate by bending a sheet of metal or joiningtwo sheets, soas to form a sharp vertical angle, inclining outward to the inner edgesof the door-plate, and so as to form a cold-air Ventilating-chamber, g,between it and thedoor-plate, the door-plate being cut away to receive'a wire-gauze frame, h, through which to admit cold air to keep theplates cool.

The products of combustion from the furnace are carried from the furnacethrough the main ilue into the chamber E', where they are deiiected atthe right and left, and into and through the heating-dues a a, back tothe front end ot' the boiler, which is providedwith a smoke box orchamber, d. This chamber is provided with an inclined movable damper ordetlector, H, which directs the smoke up and out through the smoke-stackH.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a steam-boiler, the combination of the water-spaces D, dependingfrom the crownsheet, and extending across the upper part of thecombustion-chamber, and tlie water-tubes b and b in the saidcombustion-chamber,con ber E', fire-tubes a, circular chamber d, and

structed and arranged substantially as demovable inclined deector H, allconstructed scribed and shown. and arranged substantially as describedand 2. In a steam-boiler, the combinationof the shown.

hot-air chamber E at the rear of the boiler, In testimony that I claimthe foregoing I and the air-chamber E, encircling thesai'dghothavehereunto set my hand and seal this 26th air chamber, and provided withair-holes f, day of July, 1876.

constructed and arranged substantially as dey ROBERT EHMAN. [L. s]scribed and shown. i Witnessesz.

3. In a steam-boiler, thecombination of the G. W. M. SMITH,

combustion-chamber with the hot-air cham' PHILIP MAHLER.

